PONGO 199 
middle of the forehead to the occiput, meeting the two low ridges 
from the bony orbits at its anterior end. The plane of the facial region 
is more upright than those of the batangtuensis, dadappensis or landak- 
ensis styles which have a sloping facial region, and agree in this 
respect with the genepaiensis style of the Selenka Collection. 
As is the case with all of the skulls in the Selenka Collection, there 
are no skins to go with them. 
I place as synonyms of this form Simia satyrus rantiensis and 
S. s. tuakensis of Selenka. Of the first named only immature indi- 
viduals were procured, and there is nothing in the few skulls in the 
Munich Museum to indicate what are the specific characters to war- 
rant a separation from other Ourangs. Moreover the locality assigned 
to this form, Rantai, is almost in the center of the Skalau District, a 
most unlikely place to find a species distinct from the so-called P. p. 
skalauensis. In the absence therefore of any proof that the Rantai 
specimens are distinct, it is better to drop the name from the list of 
accepted species. As for the form called tuakuwensis, it is another case 
of trying to establish a species upon young animals, and here also the 
locality given was in the Skalau District. Selenka himself seemed in 
doubt of the validity of this form, and he must have removed all 
marks to identify his specimens, for there is not a skull in his series 
in the Munich Museum referred to tuakuensis, and the name does not 
anywhere appear. It is evident, satisfied that the specimen did not 
represent a distinct race, Selenka had changed the name, and placed 
the skulls with those of another form, most probably with skalauensis. 
Wallace has given an interesting account of the Ourang-utan 
(1. c.) from which the following extract is taken: 
“In Borneo it has a wide range, inhabiting many districts on the 
south-west, south-east, north-east and north-west coasts, but appears 
to be chiefly confined to the low and swampy forests. It seems at first 
sight, very inexplicable that the Mias should be quite unknown in the 
Sarawak Valley, while it is abundant in Sambas on the west, and 
Sadong on the east. But when we know the habits and mode of life 
of the animal, we see a sufficient reason for this apparent anomaly in 
the physical features of the Sarawak district. In the Sadong, where 
I observed it, the Mias is only found where the country is low, level, 
and swampy, and at the same time covered with a lofty virgin forest. 
From these swamps rise many isolated mountains, on some of which 
the Dyaks have settled and covered with plantations of fruit trees. 
